Sharif Digital Repository

In present research in-situ groundwater remediation by permeable reactive barriers is considered and the main goal is to find the optimal dimension of reactive walls and also to find the most efficient reactive media. Here, computer simulation is done via MODFLOW. Different barrier lengths, widths, depths and distances between trenches have been considered and contaminant removal percentage calculated in all situations. Based on the research achievements increasing the barrier length has led to reduction of contaminant removal percentage because flow gradient and flow density decrease by length increase. As the results show, contaminant removal percentage increases by width increase because... 

The effects of adding nanoparticles in partitioning of α-amylase in polymer/salt aqueous two phase system (ATPS) was studied in this research. First the binodal curves of magnesium sulfate salt with PEGs 2000,3000,4000,6000 and 10000 at 23 ° C has been plotted and the suitable system which was PEG 6000/ magnesium sulfate has been selected for studying the partitioning of enzyme. Thereupon the partition coefficient of α-amylase was measured and then effect of adding silica and graphene oxide nanoparticles was investigated. It was observed that nanoparticles caused a dramatic increase in partition coefficient and yield recovery (of top phase). For further investigation the partitioning of... 

Aerobic oxidation plays important role in industrial processes and pollutant remediation. The catalysts accelerating oxidation reaction rate are included thermal (typical) catalysts such as Pt or Au on oxide supports and photocatalysts such as TiO2 or ZnO. Although well-studied Au/TiO2 system have been under deep
investigations but Au/ZnO system have less investigated because Au/ZnO has low activity relative to Au/ZnO. Gold nanoparticles supported on ZnO nanostructures were prepared through a simple chemical-thermal method and characterized by SEM, TEM, XRD, BET and photo luminescence (PL) spectroscopy. Effect of
annealing temperature on catalytic activity of these Au/ZnO... 

Enzymes, the nanometric biocatalysts that play a key role in biochemical reactions of living cells and bio-organisms, offer various applications including biosensing, bioremediation and chemical synthesis. A simple bio-conjugation procedure to surround a single horseradish peroxidase (HRP) enzyme molecule with dendritic polyester macromolecules (Polyester-32-hydroxyl-1-carboxyl bis-MPA Dendron, Generation 5) was proposed in this project. The characterization of resultant nanoparticles entitled HRP dendrozyme, was performed by TEM, DLS, GPC and FTIR spectroscopy. The results showed that HRP nanoparticles were spherical in shape and have an average size of 14 nm in diameter. Furthermore,... 

In this research we focus on fabrication, characterization and performance of biosensors based on vertically aligned carbon nanotubes. Carbon nanotubes have been used as high density carbon nanotubes and nanoelectrode array. Carbon nanotubes have been grown using plasma enhanced chemical vapor deposition method. Characterization and performance of biosensors have been studied by cyclic voltammetry and electrochemical impedance spectroscopy methods.
The mediator-less glutamate biosensor is prepared based on covalently attached glutamate dehydrogenase on vertically aligned carbon nanotubes. The biosensor has a low detection limit of 57 nM, two linear range of 0.1-20 µM with sensitivity of... 

Dependence on fossil fuels as the main energy sources has led to serious energy crisis and environmental problems, i.e. fossil fuel depletion and pollutant emission. Compared with fossil fuel, biomass is a clean energy with zero CO2 emission, because CO2 is fixed by photosynthesis during biomass growth and released again during utilization. Due to its low energy density, direct use of biomass is not convenient. Thus, it is necessary to convert biomass to fuel gas, such as hydrogen, which can be used cleanly and highly efficiently. One of the promising hydrogen production approaches is conversion from biomass, which is abundant, clean and renewable. Alternative thermo-chemical and biological... 

In recent years, because of the increase in population and more accessibility of health facilities for people, an increase has occurred in water resources consumption. Recycling water has become so much valuable as the freshwater of the world is limited. Besides the advantages of treated water has for people, discharging the untreated wastewater to the rivers could cause many problems for human health. Many kinds of pollutions, such as textile effluent, are not easy to be treated by traditional methods because of their resistance to them. As these types of wastewater have severe negative effects on living things (both humans and animals), new treatment technologies should be considered. The... 

One of the subjects that have been title for many research proposals in recent years is application of Nano Zero Valent Iron (NZVI) particles in contaminant removal from groundwater sources. Despite many studies being done, field application of this particles in a practical scale is not widespread yet which is due to many challenges like rapid settlement of particles or their unclear behavior through field application. The main purpose of this thesis in the first place is to find a practical and productive method for stabilization of particles and enhancement of their transport properties. To reach this goal, application of a natural polymer like starch has been studied as a solution. To... 

One of the most significant consequents of industrial world is environmental pollutions which displays its mortal effects in all aspects of human life including water, atmosphere and soil. After different applications of water, variable substances like organic and mineral components, toxics, heavy metal, etc is added to the water and wastewater. One of these organic components which appear in runoff and industrial wastes specially refinery companies’ is Ethylene Glycol (EG). It is used in Poly ethylene Glycol, Poly Viniles and Resin product industries, etc. In this research the effect of EG on COD removal and performance of an Anaerobic Baffled Reactor during treating Ethylene Glycol... 

The removal of ethylene glycol, one of the most widely used antifreez, with moving bed biofilm reactor (MBBR) was studied. Beside of ethylene glycol, the synthetic wastewater contained molasses and other salts as nutrient source. The packings were composed of polyethylene and shaped like small cylinders with a surface area of 500 m2 per m3 bulk volume of carriers(KMT). The COD of the feed was adjusted by varying the ratio of ethylene glycol to molasses. The total COD was 1252.5, 1345 and 1500 mg/L. The resulted showed that when the biofilm grows on the packings and its thickness is good enough, the removal efficiency increased. The increase was attributed to higher concentration of biomass... 

Cardiovascular diseases, especially coronary artery disease and coronary heart disease, are the leading cause of death in human communities. After myocardial infarction, known as heart attack, the flow of oxygen to the heart muscle cells is disrupted. It causes the death of cells that leads to structural and functional changes in the heart muscle. Therefore, specialists try to find a way to repair and regenerate the heart muscle after myocardial infarction. Tissue engineering is used to develop substantial alternatives to assist clinical therapies. Recent studies have focused on the construction of scaffolds with various advanced techniques to create guiding channels that mimic the natural... 

Photocatalytic degradation is one of the developing modern and effective methods for decontamination of hazardous pollutants of chemical industrial wastewater. This method has several advantages including the possibility of using free and sustainable energy of sun. However, it is still needed to active photocatalysts under solar light and also the enhancement and optimization of operating parameters, and consequently, these topics are selected as goals of the present thesis. Accordingly in this research, first, to obtain a photocatalyst that is highly efficient (especially under visible and solar light), multi-doping and polyethylene glycol (PEG) were used and for the first time,... 

The dairy industry wastewater has high biological oxygen demand(BOD) and high chemical oxygen demand(COD). In this study, membrane bioreactor(MBR) was used for the treatment dairy industry wastewater. Since two diffuser,submerged membrane modul and intermittent suction method were adpted to system. In this study, the response surface method and experimental design were applied as an alternative to conventional methods for the optimization of the treatment. A central composite design, with 5 replicates at the center point were used to build a model for predicting and optimizing the treatment. Mathematical model equations were derived by computer simulation programming with Design Expert... 

In recent year's acrylamide as a suspected substance for tumor growth has been studied. In some researches this topic is mentioned that acrylamide is produced by the reaction of asparagine and natural sugars. This reaction takes place only at very high temperatures during the heating process. The maximum amount of this substance is determined in fried potato products. The purpose of this study was determined to remove and reduce acrylamide formation during frying of potato. Acrylamide production when it was blanching and when it was dipped in the enzyme solution of asparaginase was examined. When potato pieces were placed in a commercial enzyme solution 200 lU/ml, acrylamide formation was... 

A Microbial fuel cell is a Bioreactor in which chemical bands are broken and their energy convert to electricity by bio-catalysts such as microorganisms and enzymes.In this project, construction, substrate investigation and optimization of operational parameters were done. Microbial fuel cell as a waste water treatment method was considered in this project. As a result, different substrate were used in anode chamber of constructed microbial fuel cell. The most important ones were waste water containing ethylene glycol and crude oil.Consequently, lack of information about cathode operational parameters was led to optimum condition selection for pH, buffer concentration and ionic strength as... 

In this study, different stages of biodiesel production from microalgae were investigated, specifically the extraction step.Various cultivation methods were also studied among which cultivation under stress was the best. Different carbon sources were also investigated to achieve highest growth. Sodium acetate with complete growth was achieved after 8 days with 6.22% fatty acid recovery. Different mixtures of solvents were compared with Blye and Dier method. Results showed that the mixture of hexane and methanol with crude lipid extraction of 15% and fatty acid recovery of 3.97% were chosen as the solvent mixture of equilibria experiments.Organic solvent composed of hexane (non-polar... 

Nowadays, Food generation has gained great importance, not only in economic view but also in political. Food reservation is as important as food generation. Synthetic polymer films has widespread use in packaging industries, that is because of its features like easily forming, low price, lightness, etc. The increase of oil resources prices and severe environmental pollution by synthetic polymers, are notable cases which led researchers to find ways in using bio polymers. Starch is one of the bio polymers which is cheap and totally degradable. Using starch in bio degradable leads to high decrease in the mix features. Nano particles are used to solve the problem.
In this study, the effect... 

The experimental investigation of biodiesel production stages from microalgae especially biomass production stage was conducted in this thesis. The optimal rate of biomass productivity was determined.
A photobioreactor was designed and constructed to cultivate microalgae C. Vulgaris according to researchers’ works and obtained results in this study. The process parameters were examined and the optimal parameters were obtained according to the necessary tests which were carried out.
According to the results, the optimal condition for growing of microalgae was obtained with aeration of 6 lit/min with 3% CO2, and CO2 injection regime of 45 sec. injection and 3 min. of stoppage. A rapid... 

Major bone defects resulted from diseases or hurts that can not heal naturally, requaire bone transplantation. golden standard for transplantation is autologus one but it has some disad-vantages such as economic burden, the lack of graft source, surgery on patient, and so on. so exploring altrnative ways led to exploit stem cells.traditionally bone marrow mesenchymal stem cells (MSCs) used for stem cell-bsaed bone regeneration. bone marrow aspiration to aquaire stem cells is painfull and give a population of cells such as hematopoetic cells that requaire to seperate and can not be handled in first passages. MSCs can be substituted by multipotent adipose tissue-derived stem cells (ADSCs) in... 

The experimental investigation of biodiesel production stages from microalgae especially lipid extraction stage was conducted in this thesis. The optimal rate of biomass productivity and optimal method in lipid extraction for biodiesel production was determined.
A photobioreactor was designed and constructed to cultivate microalgae C. Vulgaris according to researchers’ works and obtained results in this study. The process parameters were examined and the optimal parameters were obtained according to the necessary tests which were carried out. Then, several methods of lipid extraction using different solvents such as chloroform, methanol, and n-hexane were investigated and the best...